Road cycling in urban environments and on country roads poses unique hazards to the cyclist because of the presence of motorized vehicles, especially cars and trucks. In urban environments, the advent of bicycle lanes has helped alleviate somewhat the danger of being struck from behind by an approaching car or truck, although the prudent cyclist attempts to stay ever alert to automobile traffic. The lanes of county roads frequently have narrow shoulders and cars and trucks may approach less frequently and often at higher speeds demanding of the cyclist a vigilance that can sometimes detract from the enjoyment of the ride. The growing popularity of group cycling for races, charity rides, and for increased safety in cities and in the country has helped reduce crashes with motorized vehicles, although even an encounter with another approaching bicycle can be quite hazardous, particularly at the speeds achieved by modern experienced cyclists riding in close formation or whenever large groups of riders congregate.
In the past, minors or other optical viewing systems have been mounted on helmets and glasses to enable a cyclist to see what is approaching from behind. However, these systems typically are somewhat obtrusive and bulky, especially in their attachment to the cyclists' gear, may interfere with the cyclists' forward vision, and have generally not necessarily been widely adopted and used. It would be desirable to provide a less bulky and obtrusive rearview system for a cyclist, especially of the type that even an experienced cyclist would choose to wear and use, and that could provide a sufficient line of sight to indicate an approaching vehicle without providing an undue distraction to the cyclist or interference with their forward and peripheral vision.